Method for compacting empty plastic containers and press for carrying out said method

ABSTRACT

According to the invention, in order to transport empty PET containers, said containers are compacted to form a packet ( 18 ) and are held in the compacted state by means of encompassing means ( 28 ). In this way, the transport volume of the containers is significantly reduced.

REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the European Pat. application No. 01 124 371.4 of Oct. 24, 2001 of which the contents are included in the present application by reference thereto.

TECHNICAL FIELD

The invention relates to a method according to the introductory portion of claim 1. The invention relates further to a press for plastic containers according to the introductory portion of claim 14.

PRIOR ART

Whereas in many countries a tradition of reclamation in the areas paper, glass, metal and organic refuse exists since many years and the markets of these materials have began to run more or less smoothly, the reclamation of plastic wastes is still comparably seldom. The separate collecting and reclamation of plastic containers is ecologically superior to their burning. In order, however, to consider the reclamation a sufficient minimal amount of same plastic materials must be present. This is the case in the field of the PET-beverage containers. A substantial advantage of PET (polyethyleneterephthalate) versus many other plastics consists in that this material can be processed further during the reclamation to high quality products, that is that no downcyling occurs.

Due to the worldwide rapid spread, PET has achieved a large importance in the packing industry and has gotten to become a sought after raw material. For this reason a large demand exists for reclaimed PET, PET belongs to the plastic materials with a small environmental impact during the production and the waste management. Among other, following possibilities of use exist in the textile field as filling material for cushions, fibers for sport and fleece jackets, backpacks, sport shoes, carpet coatings, etc. In the field of containers yogurt containers, margarine and biscuit containers, etc.

For the production of reclaimed PET the decentralized collected PET-bottles are transported to logistic centers where they are sorted according to color and quality and are processed to compacted bales having a weight of from 100 to 300 kilograms, which can be stored temporarily. Thereafter, the processing of the sorted bottles to reclaimed matter follows, whereby it is checked manually and by machines if all foreign matter has been removed. Thereafter, the labels are detached by steam and removed. The bottles (including closure caps) are reduced in mills to shavings. These are pre-washed, in order to be cleaned thereafter in a second washing process from adhering residues of adhesives. The washing liquid can be used again for further washing processes. The clean sheavings are separated according to the kinds of plastic PET (bottle bodies) and Polyethylene(caps) according to their different densities (PET sinks in water, but polyethylene swims) and thereafter dried, dust is removed as well as possible remaining metal particles. In a last process step the shavings are homogenized in large mixers to charges with precisely defined values, filled into transport bags and passed on to the respective processing stations.

The decentralized collecting and the following transporting of the empty PET-bottles requires corresponding expenditures. Collection containers are placed at retail trade businesses, in dining establishments, offices or at recreation areas. All collected PET-beverage containers are brought thereafter by transport companies to one of the PET-logistic centers in which the reclaiming production occurs.

In order to arrive at a as small as possible transport expenditure from the collecting areas to the logistic centers the reduction of the volume of the returned PET-beverage bottles is of a substantial importance. By means of this measure the number of transports can be reduced which is of a positive influence regarding the costs on the entire chain of logistics and accordingly the price of the reclaimed PET. PET-bottles can be compacted during all steps of the disposing chain. Ideally, the compacting to a flat state should happen, however, as early as possible.

According to the prior art the PET-bottles are compressed not at all, or then manually or by various kinds of presses and filled loosely into large plastic bags having a size of e.g. 100 Liters. Depending from the kind of the compacting of the bottles total compacting grades of the bottles prepared for transportation amounts from 0% to about 40%.

It is known to compact PET-bottles to bales or packages and to hold these together by straps. Such packages lead to a higher total compacted state and require, therefore, less transport capacity. The documents JP-A-2000 095219, JP-A-2001 259893 and JP-A-2001 087894 disclose large compacting plants in which a large number of PET-bottles are compacted simultaneously by one single compacting movement in a compacting chamber and are, thereafter, ejected in a compacted state through a channel of the pressing plant. At the end of the channel a step-wise exiting the channel takes place and straps are placed around the compacted package. These compacting plants are quite large and, therefore, not suitable for a direct use in stores. Initially, enough bottles must be collected at these compacting apparatuses until they can be compacted in one step to a package. The EP-A-0 941 941 discloses various variants of waste compacter, whereby the compacting occurs into one respective waste bag. At a package of PET-bottles, which expands after the release of the compacting pressure, no large compression can be reached by these presses because the compacting plate must be moved out of the bag when retrieving the bag from the press. The U.S. Pat. No 5,056,428 discloses the compacting of vehicle tyres whereby no enclosed compacting chamber is foreseen for this process. The GB-A-1 537 659 discloses a bale press for office waste and cardboards waste.

SUMMARY OF THE INVENTION

The initial object of the invention is to provide greatly compacted packages of PET-containers by a simple and space saving procedure. This allows the provision of such packages also in shops and stores where the containers are returned individually or in small numbers and at various times.

This object is solved by the method of the kind set forth above and the characterizing features of claim 1.

Because the production of the package proceeds in a plurality of steps, respectively newly added containers can be added directly to the already compacted containers in the press, such that no separate storage chamber is necessary for the containers. This leads to a substantial reduction of the apparatus for compacting the package.

The wrapping or encasing of the packing occurs preferably in the same compacting chamber in which the package is compacted. Thus, the compacting apparatus can be designed still smaller, because no separate channel for a emitting of a compacted package and for its subsequent wrapping. The container to be added is preferably compacted directly on the partial package.

The package is held together by the wrapping means so that it forms a unit suitable for transport. The wrapping means retains, thereby the package in a compacted state, so that the compacted state of the finished package as transportable unit corresponds substantially to the one of the compacting the containers to the package. As wrapping means preferably cords or straps can be considered, which are placed around the containers in the state compacted into a package.

The forming of the package proceeds preferably in a container press which compacts the individual containers before or after the forming of the package. The forming of the package is, however, possible also in a separate press.

The packages are preferably of a square or cubical shape in order to provide transport units which are to the placed for transport closely side by side. For ease of handling packages have preferably a weight from 10 kilograms to 20 kilograms.

The invention is based, furthermore, on the object of providing a press by means of which a substantial increase of the total degree of the compactness of a plurality of containers and, therefore, a substantial reduction of the transport volume of a given amount of containers can be arrived at.

This object is met by a press design with the characterizing features of claim 14.

Because the press comprises, besides the compacting means for compacting individual containers, or possibly simultaneously a plurality of containers further means by means of which a compacted and wrapped held package may be produced from the compacted containers, a considerably larger total degree of the compacting and a correspondingly considerably lower transport volume, respectively can be arrive at.

BRIEF DESCRIPTION OF THE DRAWINGS

Below, exemplary embodiments of the invention are explained more in detail with reference to the drawing, whereby

FIG. 1 illustrates a package of compacted PET-bottles held together by straps;

FIG. 2 to FIG. 9 illustrate a example for the compacting of a package by means of a manual press;

FIG. 10 illustrates a schematic view for the explanation of the superimposed compacting of the package;

FIG. 11 illustrates a detailed view of the compacting plate and the holding means;

FIG. 12 illustrates a simplified view of a motor driven press;

FIG. 13 illustrates a simplified view of the back side of the press;

FIG. 14 illustrates a detailed view of the support of the compacting plate; and

FIGS. 15 to 20 a example for the wrapping of the package in the press.

BEST WAY OF EMBODYING THE INVENTION

FIGS. 1 to 9 illustrate schematically the procedure according to the invention. The empty PET-bottles are, thereby, compacted to a package 18 such as schematically illustrated in FIG. 1, and the package is held by wrapping means illustrated in FIG. 1 as straps 28, so that a transportable unit is arrived at. It has been proven that with this procedure a total compacting grade of about 70-80% can be achieved. The preferred embodiment according to the invention relates thereby to the preparing of PET-bottles for transportation. The invention is, however, not restricted to this example, but is generally suitable for compacted plastic containers. Below, however, reference is made as example to PET-bottles.

The producing of a compacted package of bottles can proceed variously. Preferred and hereinafter still described in detail with reference to a press is a procedure according to which the individual bottles are compacted in a press and simultaneously compacted in this press to a package. The wrapping means around the completed package is placed into this press, too, so that the completed package can be removed from the press. A proceeding according to a different kind for producing packages is, however, also possible: Accordingly, for instance, individual or several bottles can be compacted in a first press. Immediately afterwords or after a temporary storing, the already compacted bottles are compacted and held together by wrapping means as package in a further press which has a compacting chamber in accordance with the desired shape of the package. The press used thereto can include e.g. a square shaped compacting chamber which is closed off at its top side by a compacting plate, which after the filling of the compacting chamber with a amount of bottles corresponding to the desired size of the package or the desired weight of the package, respectively, reduces the compacting chamber operated manually or by a motor, so that the bottles are compacted into a package shaped block. This block is then wrapped by e.g. straps or cords so that the package is produced. The wrapping will be explained in detail later with reference to a embodiment.

A different procedure can be followed also in such a way, that the not compacted bottles are filled in a sufficient number into a compacting chamber which corresponds to the desired shape of a package, whereafter a compacting plate compacts the bottles and also forms the package of the compacted bottles in a single processing step. Also in this case the package is again stabilized regarding its shape by the wrapping means, so that it forms a transport unit.

The produced packages are preferably of a square shape and have a weight of about 5-20 kilograms wherewith a easily manageable transporting shape for the bottles is arrived at. Obviously also other, e.g. cubic or cylinder like shapes are possible for the package. Depending from the filling of the bottles into the compacting chamber a more or less orderly position of the bottles inside of the package is arrived at. Thereby large, i.e. 1 liter to 2 liter bottles are oriented often in the longitudinal directions of a square shaped package. Smaller bottles are encountered oriented also in the longitudinal direction, but also oriented laterally or obliquely. The bottles can, thereby, have caps or be without caps, whereby it is preferred that e.g. needle or spine shaped elements are foreseen which can cause a puncturing of closed bottles. Such a puncturing is, thereby, always ensured if, as will be described later, the bottles are compacted individually.

As already mentioned, straps or cords which hold the package together can be used as wrapping means. As holding together shall be understood that a transportable unit is produced, which as a rule is ensured if the wrapping proceeds at a compacted package. By the restoring property of the compacted bottles a force acting onto the wrapping means is produced which prevents a loosening of the wrapping means. By means of this the package is kept in the compacted state. Instead of straps or cords it is also possible to use a foil, e.g. a shrinking foil as wrapping means which holds the bottles compacted into a package shape together. Also a bag can be used, whereby it then, in contrast to the prior art, does not contain empty bottles but encases the bottles compacted to a package shape in such a manner, that the compacted package shape remains maintained.

Below, a preferred method and a preferred press, respectively, for the production of the package shaped transport units of the PET-bottles will be described more in detail. FIGS. 2-9 disclose, thereby, different steps of the compacting of a bottle and the adding thereof to the package. In FIG. 2 a part of a press 20 is illustrated which includes a supporting frame 10 at the top side of which a manual press 11 is located. In this embodiment the manual press 11 is a manually operated toggle lever press which includes a only partly illustrated manual lever 14 by means of which the compacting can be carried out. Not illustrated toggle levers act from the manual lever 14 onto a compacting plate 15, whereby this compacting plate is formed preferably of a plurality of individual compacting members 15′ located at distances between each other (FIG. 11) and which form between them openings 15″. A moveable delimiting element 19 (bottom compacting plate) located below opposite the compacting plate 15 forms a support for a already formed partial package 18′of PET-bottles and which is illustrated simply as a block. This package is delimited circumferentially by not illustrated sidewalls of the press, whereby these sidewalls form together with the bottom compacting plate the actual compacting chamber which is delimited at its upper side by the upper compacting plate 15 which can immerge into the compacting chamber. Furthermore, retaining means 16 can engage into its upper area, which in this embodiment are formed by a plurality of disks having the shape of a cut-out of a circular disk, which are pivotable around a pivot axis 16 and which are arranged in such a manner that they are located within the area of the openings 15″ of the compacting plate 15. The retaining means could also be linearly displaceable plates which can be laterally moveable into and out of the compacting chamber. However, pivotable retaining means are preferred. FIG. 2 illustrates, thereby, a initial position in which a partial package 18′ of compacted bottles is already present in the compacting chamber, which partial package lies on the bottom compacting plate 19 and is retained by the retaining means 16 from above in a compacted state. FIG. 2 illustrates further that a further bottle 17 to be compacted has been placed into the press. This has occurred in the illustrated example by a lateral inserting into the empty space below the compacting plate 15 and above the retaining means 16. The bottle 17 lies, thereby, on the preferably curvilinear front surfaces 16″ of the individual disks of the retaining means 16. FIG. 3 illustrates a first step which is arrived at after the placing of the bottle 17 by the operation of the manual lever 14 thereinto. It is usually pressed by the operating person from the illustrated position downwards. The retaining means 16 are, thereby, pivoted around the pivot axis 16′ away from the partial package, so that it is released from the retaining means which can be seen in FIG. 4. The partial package 18′ expands thereby due to the restoring force of the bottles held therein in a compacted state upwards towards the compacting plate 15, so that the bottle 17 to be compacted lies on the upper side of the partial package 18′. Due to the expanding of the partial package a first compacting of the bottle 17 can already occur. By a continued pressing down of the operating lever 14 the compacting plate 15 is now pressed downwards in a direction onto the compacting plate 19, so that such as can be seen in the FIGS. 5 and 6 a compacting of the bottle 17 as well as a pressing down of the partial package 18′ is arrived at. The thereby compacted bottle 17 is therewith added to the partial package and the partial package is compacted again. In FIG. 7 the compacting disk 15 has reached its bottom dead center position and has compacted the partial package, now completed by the bottle 17 so for that the upper side of the partial package 18′ is located below the bottom sides of the retaining means. These are again pivoted over the partial package 18′ and arrested in this position. The operating lever 14 has reached its lowermost position. When releasing same the operation lever the compacting plate 15 is moved again upwards by the retaining means 16 (FIG. 8) so that in FIG. 9 the space above the retaining means 16 is again free for a depositing of a further bottle 17. The retaining means keep the partial package 18′ arrested in the compacting chamber in a compacted state. The compacting and adding to the partial package of a further bottle 17 proceeds now again in accordance with the FIGS. 2 to 9. In this embodiment the retaining means 16 are accordingly coupled for movement to the compacting plate, e.g. through a lever arrangement. However, also rigid, stationary retaining means may be arranged which do not pivot away as long as the compacting plate can press the container through the retaining means onto the partial package and this partial package is retained sufficiently.

In order to enable the forming of a package in the compacting chamber the lower compacting plate 19 is mounted for a movement in the vertical direction. When no partial package has as yet been formed in the press, the lower compacting plate 19 has been displaced completely upwards so that the first bottle of the package is compacted between the compacting plate 15 and the compacting plate 19. Each of the further bottles being added increases the respective force acting onto the lower compacting plate 19 at the lower dead center position of the upper compacting plate 15. The lower compacting plate 19 is thereby preferably arranged for a downwards movement in such a manner, that it upon a exceeding of a predetermined force displaces downwards by one unit of length wherewith the compacting chamber increases regarding its volume. Obviously, the volume increase of the compacting chamber can also be achieved in a way different than depending from a force, e.g. every time after a predetermined number of compacting operations. Then, further bottles can be added in the increased compacting chamber to the partial package now being formed, whereby every time again, when the increasing number of packages leads to a reaching of the triggering force for the lower compacting floor 19, a further downwards displacing thereof by one unit of length takes place (in place of a displaceable press bottom 19 it could also be foreseen to have a compacting plate 15 with a variable maximal compacting stroke). With this procedure a stepwise forming of the partial package 18′ in the compacting chamber takes place. This process is terminated when the compacting plate 19 has reached the lowermost point of its possible path of displacement. In this instance the package is complete or is possibly further completed until also then the maximal allowable pressing force is arrived at. A corresponding annunciation can indicate to the operator that now the package has been completely formed in the compacting chamber. Then, initially a position according to FIG. 9 is arrived at, whereby the package 18 is now the completed package and no longer a partial package. The package is now in the compacted position, retained by the upper compacting plate 15 or the retaining means 16 in this position in the compacting chamber of the press 20. Now, following this, the wrapping means are placed around the package such as still will be explained, and thereafter the package can now taken out of the press after a further lowering of the lower compacting plate 19 and/or after a displacing upwards of the upper compacting plate 15. FIG. 9 illustrates the retaining in the compacted state by retaining means 16, it is, however, preferred if at the end of the forming of the package the compacting plate 15 compresses the package and the wrapping with the straps proceeds in this compressed position.

FIG. 10 illustrates a preferred partial aspect during the compacting, according to which during a compacting of the partial package 18′ or package 18, respectively by the compacting plate 15 a compacting takes place, during which the bottom side of the compacting plate is displaced further downwards by a predetermined amount d, preferably 10 to 60 millimeters, preferably about 20 millimeters, than the bottom edge of the retaining means 16. It has been proven that by this compacting of the package further downwards than actually needed for a pivoting inwards or moving in of the retaining means, the restoring force of the package is decreased considerably, about by the factor 10, so accordingly the retaining means and its support, respectively have to absorb smaller forces which simplifies the design of the press distinctly.

FIG. 11 illustrates a more detailed view of a press 20 designed in a partially open manner, in which view the toggle lever operation of the compacting plate 15 as well as its design consisting of individual plates 15 with openings 15″ between them can be seen better. Also visible are the individual disks of the retaining means 16 with their pivot axes 16′ as well as the dropping-in opening 21 for empty bottles. Not illustrated is the connection of the axes of the retaining means to the lever for the driving of the upper compacting plate.

FIG. 12 illustrates schematically a view of a motor driven press, whereby this press operates basically in the same way as the above disclosed manual press. In place of the manual operating, however, a motor driven press with a motor 31 is foreseen and a automatic charging which charges the bottles automatically from a double trough 32 into the press.

The trough 32 rotates, thereby, after the depositing of a container to be compacted thereinto, so that it is moved towards to compacting chamber.

Some reference numerals as used until now identify thereby parts of this motor driven press 20′ having the same function. The drive of the levers for the upper compacting plate 15 comes from the motor, e.g. through a transmission arrangement with a chain drive. The retaining means 16 are moved e.g. over a cam disk, so that they are also driven by the motor 31. A pivotable plate 32′ can always safely empty the trough 32 and transport the container to be compacted into the compacting chamber and close it off against the through 32 during the compacting process.

FIG. 13 illustrates the backside of the motor driven press 20′. The wrapping straps are fed into the compacting chamber through strap feeders 33. There, they can be guided in channels 35 of the lower delimiting element 19, so that the package is formed above the straps. The straps are guided at the front side 36 and inside of the compacting chamber again upwards so that they extend along both sides of the package. When the package has been compacted completely, the straps are brought through feeding means at the upper side of the package through the compacting plate 15 which retains the package in the compacted state from the back side of the press to its front side, connected there to the free end of the strap, e.g. welded and are then cut off.

In this example the lower delimiting part 19 is mounted to a driven, rotatable threaded spindle 50 (thread not illustrated.), so that the bottom plate 19 is driven and displaceable upwards and downwards. When the compacting force has grown that large that the spring 51 is compressed so much that a contacting occurs of the sensor 52, the lower delimiting part 19 is every time moved downwards for a increasing of the compacting chamber until the distance of the sensor corresponds again to the set distance or is displaced downwards by a predetermined measure.

Alternatively, the compacting bottom or the lower compacting plate 19 could be at the already described manual press 20 e.g. supported for a displacing in a roller guide at the frame of the press 10. The lower compacting plate 19 could be attached to a chain which is guided and connected through a sprocket wheel to a friction clutch. The friction clutch is a off the shelf element which, when exceeding a predetermined force rotates through a predetermined angle of rotation. In this way a displacing downwards of the compacting floor 19 occurs if a predetermined force act thereonto which exceeds the set force of the friction clutch. The coupling keeps on rotating until the acting force falls again below the set predetermined force; accordingly, the compacting bottom moves during the same time span also downwards. Thereafter, the pressing can again proceed at this level position of the compacting plate 19 until the set force of the friction clutch is again exceeded. The limiting of the compacting force by the friction clutch can additionally avoid a distruction of glass bottles which have been deposited erroneously in the press. The friction clutch allows, furthermore, a substantially free displacing upwards of the compacting floor 19 when the package has been taken out of the compacting chamber. To this end the clutch is disengaged. In order to displace the compacting bottom 19 upwards not illustrated manually or motor driven operating means can be foreseen.

The FIGS. 15 to 20 illustrate the placing of a wrapping means around the package in a simplified manner, whereby in the illustrated example it is a cord or a strap 38 which can be pulled off a reel 40. In the Figures the press is, thereby, illustrated schematically only and only as far as necessary for the understanding of the wrapping procedure. FIG. 15 illustrates how the cord 38 or possible a number of adjacent cords 38 located at distances between each other, is pulled over the compacting floor 19 in its upper position after a already formed package has been removed from the press. The door 22 of the press is, thereby, open. The cord 38 is now pulled over the compacting floor 19 and thereafter the door 22 of the press is closed and the cord 38 is pulled further out of the press. This can be seen in FIG. 16. In the illustrated example the part 45 of the cord which hangs down freely at the front of the press forms together with the reel 40 a supply of the wrapping means which is used for producing the package. FIG. 17 illustrates a formed partial package 18′ during the forming of which the lower press floor 19 has been moved downwards so that at the front and the back in the compacting chamber a cord section 41 and 42 has been pulled further from the front free end 45 and the reel 40, respectively. In FIG. 18 the package 18 has been completed and the cord 38 is pulled from the rear over the free upper end of the package which is indicated in the drawing by a hook 43. Because the upper compacting plate 15 consists of individual sections which define between themselves a empty space it is possible to pull the cord 38 from the rear through the compacting plate 15 over the package. FIG. 19 illustrates how the two cord ends are connected at the front, upper side of the package, after cutting the cord, to a knot 44. The same is made with all possible further cords placed around the package according to the described procedure. The knot 44 is thereby produced as long as the package is subject to a pressing by the compacting plate 15. Only after the knotting of the cords the upper compacting plate 15 is displaced upwards so that the package 18 lies freely which can be seen in FIG. 20. The package can then be removed whereby the compacting floor 19, as described, is displaced downwards, whereafter the process according to FIG. 17 begins anew. At the previously illustrated motor driven press the procedure is similar, but the strap supply is preferably on the reel and is pulled off the reel when forming the package.

Instead of the illustrated cords or already explained weldable straps it is also possible to use e.g. plastic straps which are closed by a clamp to a wrapping. Corresponding systems are known and must not be described herein further. 

1. Method of producing a transport unit (18, 28) of substantially empty, compacted plastic containers (17), specifically of not sorted PET-bottles, for a transporting thereof to a reclamation site, whereby a respective plurality of containers (17) is compacted into a package (18) and retained by wrapping means (28, 38) in a package shape and is provided in this manner as transportable package and the wrapping means (28) retains the package in a compacted state and is a wrapping means (20) or a encasing means which is placed in a state of the package held compacted around same, characterized in that the forming of the package proceeds in a plurality of steps by adding individual or several containers (17) to a already compacted partial package (18′).
 2. Method according to claim 1, characterized in that the containers are compacted prior to the forming of the package or the partial package.
 3. Method according to claim 1, characterized in that the containers are compacted during the forming of the package or partial package.
 4. Method according to one of the claims 1 to 3, characterized in that a compacting of the container proceeds in the same press (20) in which the package is formed.
 5. Method according to one of the claims 1 to 5, characterized in that a compacting of the container proceeds in a first press and the compacting of the package proceeds in a second press.
 6. Method according to one of the claims 1 to 5, characterized in that a compacting of the containers (17) in the press (20) proceeds at the one side between a compacting plate (15) and at the other side a partial package (18′) of containers.
 7. Method according to one of the claims 1 to 6, characterized in that a partial package is maintained in a compacted state in the press (20) by means of retaining means (16,16′).
 8. Method according to claim 7, characterized in that during the compacting of the partial package a compacting to a smaller package size, preferably down to 10% to 30% smaller partial package size than given by the retaining means occurs.
 9. Method according to one of the claims 1 to 8, characterized in that the containers are punctured open during the compacting, specifically by puncturing means (15′) located on a compacting plate (15) of the press.
 10. Method according to one of the claims 1 to 9, characterized in that a container to be compacted rests initially on retaining means (16) which keep the partial package in a compacted state, that the retaining means upon a moving of the compacting plate (15) of the press (20) in a direction towards the partial package (18′) releases same, so that the container is compacted between partial package and compacting plate.
 11. Method according to one of the claims 1 to 10, characterized in that the wrapping means (28) or encasing means is placed around the package in the compacting chamber.
 12. Method according to claim 11, characterized in that the wrapping means or encasing means is placed around the package during which it is held by the compacting plate (15) of the press or by the retaining means (16, 16′) in a compacted state.
 13. Method according to one of the claims 1 to 12, characterized in that the wrapping means is formed by plastic straps of which the ends are welded together.
 14. Press (20) for the production of a transport unit (18) of compacted plastic containers (17), which press (20) is provided with a compacting chamber, and a compacting means (14, 15) for a compacting of containers (17) to be compacted into a package (18) and received in the compacting chamber and includes a wrapping arrangement which has at least one wrapping means (28, 38) adapted to encase the packages compacted into a package in a compacted state which remains at the package, characterized in that the press is designed for the forming of the package in a plurality of steps by a adding of individual or several containers (17) to a already compacted partial package (18′), and includes retaining means (16, 16′) by means of which the partial package is arrestable in the compacting chamber in a compacted state.
 15. Press according to claim 14, characterized in that the retaining means comprise a plurality of retaining disks (16,16′) which are adapted to be moved or pivoted into the closed compacting chamber.
 16. Press according to claim 14 or 15, characterized in that the retaining means are connected for movement with the press drive or include a own drive which is coupled regarding control to the press drive so that the retaining means are insertable into and removable out of the compacting chamber independent from the position of the compacting plate (15).
 17. Press (20) according to one of the claims 14 to 16, characterized in that the volume of the compacting chamber is adjustable by at least one moveable, specifically compacting force dependent moveable delimiting element (19) opposite of the compacting plate (15) between a minimal volume and a maximal volume.
 18. Press (20) according to one of the claims 14 to 17, characterized in that the retaining means are designed as at at least one upper limit of the compacting chamber as retaining disks (16) pivotable around a pivot axis (18′) into the compacting chamber and pivotable out of same, respecrively, and that a plurality of retaining disks are arranged at a distance from each other on a common pivot axis.
 19. Press (20) according to one of the claims 14 to 18, characterized in that the compacting means is a compacting plate (15) which has recesses through which the compacting plate is able to move through the retaining means.
 20. Press (20) according to one of the claims 14 to 19, characterized in that the wrapping means is adapted to be guided from the wrapping arrangement into the compacting chamber and upon a increase of the compacting chamber to be drawn off a supply.
 21. Press according to one of the claims 14 to 20, characterized in that the wrapping means is formed by a plurality of straps, each of which adapted to be drawn off a spool into the compacting chamber and guided in recesses of the delimiting element (19). 